1. Field of the Invention
The present invention relates to a static mixing module and mixing apparatus, and more particularly to a static mixing module for statically contacting and mixing two or more kinds of fluids (gases, liquids, powders, etc.) in a pipe, and a mixing apparatus including one or more static modules placed in a pipe.
2. Related Art
A static mixing module is usually placed, singly or in combination of two or more modules, in a pipe having a predetermined length and inner diameter to promote the contact and/or mixing of a plurality of kinds of fluids (gases, liquids, powders, etc.) which flow into the pipe. When mixing a gas and a liquid, the static module serves to introduce fine bubbles into the liquid.
U.S. Pat. No. 3,923,288 discloses in its FIG. 2 a low cost module capable of forming a mixing matrix which induces a complex velocity vector in the axial direction of a pipe. Disclosed in FIG. 3 of the above-described U.S. Patent is a mixing module of another type having a mirror-image relationship with the mixing module shown in FIG. 2 of the U.S. Patent. U.S. Pat. No. 4,220,416 also discloses a similar static mixing module in its FIG. 7.
These mixing modules basically have the same configuration as shown in FIG. 19. In these modules, an elliptical plate having wing portions is first formed by blanking, and the wing portions are then alternately bent in the upper and lower directions as viewed in FIG. 19 by two bending operations so as to obtain a configuration in which the wing portions extend in four different directions.
However, the above-described modules require two kinds of dies to carry out the two bending operations, resulting in an increased costs of blanking. Machining costs also increase due to the increased number of bending operations.
The module shown in FIG. 20 is also known as having a high mixing efficiency despite of its relatively short length and low pressure loss. To manufacture this module, pieces (wing portions) having the shapes shown in FIGS. 21A, 22A and 23A are first formed by press working and are then assembled and subjected to welding to obtain the three kinds of blocks shown in FIGS. 21B, 22B and 23B. These blocks are assembled and welded to each other to obtain the structure shown in FIG. 20. The details of this module are disclosed in Japanese Patent Publication (kokoku) No. 61-32117.
In the above-described manufacturing method, the pieces can be obtained by blanking or press working only. This simplifies the die for press working and easily guarantees the accuracy of each part. However, the kinds and number of parts must be increased considerably to conform with variations in the dimensions of a pipe in which the module is to be disposed. This increases the difficulty in selecting parts and managing supplementation of parts, leading to problems in quality control, such as mixing of foreign parts. Further, the manufacturing method is disadvantageous from the viewpoint of the production costs and the production efficiency. The necessity of a special welding machine for welding many welding points also increases the production costs.